In present day communication systems, particularly those employing transmission links from a central television outlet to subscribers or viewers, in order to alert the television viewers to an emergency situation, it is desirable to provide a normal transmission over-ride so that emergency civil defense information, such as relating to national or local disaster, such as storms, fire, floods, etc. can be presented immediately to as large a group of the citizenry within a jurisdiction as possible.
The present invention involves a system, particularly adaptable for cable television systems, which permits central control of the distribution of visual and audio presentations from a television system, so that the normal programming will be interrupted and emergency civil defense information provided to the viewers connected to the system.